A common logistical concern in businesses is the tracking of assets or persons. In retail, one example of this logistical tracking concern is shoplifting. Many retail establishments employ electronic tags attached to goods that can be detected by systems installed for that purpose. A common term for these systems is electronic article surveillance, or EAS.
Many of these tags and systems are only capable of registering the presence of the tag. Transmitters and receivers are located at exit points within a retail environment. The transmitter creates an interrogation zone at the exits to the retail establishment, while the receivers scan for responses from tags passing through the interrogation zone. The transmitters and receivers are typically housed in pedestals. There are several types of tags for these systems, one of which is a harmonic tag and another of which is a resonance tag.
With the harmonic tag, the electromagnetic interrogation field creates stored energy in the harmonic tag. When the interrogation field is turned off, this energy dissipates from the tag and produces a signal which is a harmonic of the interrogation field. The element that stores and dissipates the energy to generate the signal is typically comprised of a ferrite core with a wire coil around it, and it can be tuned to generate a signal at particular frequencies. The system is tuned to the expected frequencies, and the receiver antennas of the system detect these signals. When a signal is detected within an interrogation field, it is assumed that a tag is present and that it is improperly being removed from the retail facility. Similar systems may also be used to identify authorized personnel at control points, etc.
There are many ways used to attach a tag to an article being protected. For clothing and similar items, a tag incorporating a tack is frequently used. The tack has a head with a shaft extending from its head. In one of the many embodiments of the EAS tag, the tack may be included in the cap component of the EAS tag, while the body component of the EAS tag may house a clutch that has an aperture through which the tack shaft may be inserted into the clutch. Various clutches are employed in the art, and depending on the particular clutch, the clutch may be released by mechanical means, application of a magnet to the clutch, or by many other methods.
One clutch that is frequently used is a ball clutch. In a ball clutch, a spindle is located in the interior of a tapered cup which is opened at its larger end and has an aperture through its smaller, closed end. The spindle has a hollow shaft through it which is aligned with an aperture in the tapered cup. Both the aperture in the tapered cup and the hollow shaft through the spindle are at least large enough to accommodate the insertion of the tack shaft. The spindle has apertures through its walls which carry ball bearings that ride on the interior of the tapered cup. When the tack shaft is inserted, the spindle moves to accommodate the shaft. If the shaft is then pulled in an attempt to remove it from the spindle, the ball bearings, the tack, and the tapered cup wedge. The spindle must be retracted prior to pulling the tack, in order for there to be space among the elements within the tapered cup to allow the removal of the tack shaft. In many ball clutches, the spindle is at least partially made of a magnetically attractable material, which allows it to be retracted by application of a magnet.
In many applications, it is desirable that the EAS tag be as small as possible. However, due to the shapes and sizes of the internal elements, the possible arrangements of the internal elements are limited. Some of these possible arrangements result in tag shapes which are vulnerable to tampering. For example, a tag with an elongated shape can provide sufficient purchase so that the cap and body components can be gripped and twisted to separate these two components.
Some embodiments of the current invention include benefit denial systems for theft deterrence. Such benefit denial systems could be used in lieu of, or in addition to, systems employing electronic surveillance elements and/or anti-twisting features. A common form of such a benefit denial system incorporates the use of frangible ink compartments, ampoules, or vials. In the event that a thief attempts to forcibly remove the tag from the item attached to it, the bending or pulling on the tag causes one or more ink compartments to rupture, releasing a staining dye, ink, or other staining agent from the ruptured compartment and onto the attached item. Ink or dye-based systems are often used on clothing items. The destruction of the clothing by staining serves as a deterrent from carrying out the theft.
The prior art for such ink tags has generally included one or more ink compartments located in the tag interior, in close proximity to the tack shaft, in order to facilitate immediate contact of the ink to the clothing. While such arrangements have utility, it could provide an additional advantage to theft deterrence efforts, to have the ink/dye compartment prominently presented on the tag to serve as a visual deterrent, thus making it obvious that attempts to forcibly disengage the item from the surveillance tag will cause the ink or dye to stain the item.
Another common feature of prior art tags is that they are not reusable in the event of breakage to the ink compartment. Due to the location of some ink compartments, breakage causes contamination of the entire tag, so as to cause destruction to any EAS signal elements that may be located within the surveillance tag. The surveillance tag is difficult to clean and the ink vial is often sealed within the enclosure such that a broken vial is often difficult or impossible to replace in the retail setting. Some embodiments may include an ink-based surveillance tag in which the ink compartments would be replaceable. In addition to or in lieu of this feature, some embodiments may be constructed such that at least a portion of the surveillance tag could be easily reused with a minimal amount of clean-up and reconditioning in the event of an ink compartment breakage.